A sorting device for flat mail items is known, for example from the WO 95/02468. It is standard practice to feed the mail items to the sorting device by means of a conveyor belt, which comprises several successive processing stations along a horizontal, straight transporting section. Processing stations of this type are input stations, for example, in which the mail items are supplied by side belts to the conveyor belt. Other stations, for example, are an alignment station, a viewing station, an ejection station and subsequently installed printing stations for imprinting the mail items with signatures corresponding to the delivery addresses.
In the viewing station, the position of the mail items is checked and the delivery address read in. The subsequently installed ejector device then removes incorrectly positioned mail items from the belt toward the side. Addresses with unclear printing are transmitted to a workstation where they are corrected. Owing to the fact that this process requires a longer period of time, the section between the viewing station and the final processing must be correspondingly long.
An intermediate storage area is described in the U.S. Pat. No. 4,986,423, in which letter shipments are transported at different levels while clamped between a system of cover belts with relatively small deflection radii.